Formerly believed to have a widespread Western Pacific distribution but apparently restricted to southern Japan (G.R. Allen pers. comm. 2009). Populations from other areas are currently assignable to A. jenkinsi (Everman and Seale 1907).

Justification:Apogon notatus has been assessed as Least Concern. It is found in the southern islands of Japan and is common. While the coastal locality of this species overlaps with areas of high pollution levels and disturbance from boats, it is reportedly common in areas of its range where these factors are present. This species is known from rocky reefs in bays and harbours, illustrating a lack of habitat specialism and a degree of tolerance to pollution.

Apogon notatus is found around rocky reefs in bays and harbours, hovering near reef crevices and caves. During certain parts of the year it regularly forms large, dense aggregations during the day.

About two months before spawning, when water temperature exceeds 16oC, females establish territories over rocky substrate. Males join the females in these territories and form breeding pairs. During the reproductive season, (June - September in Japan) spawning occurs daily. The males of this species mouthbrood the fertilised eggs until they hatch.

Apogon notatus is associated with rocky reefs in harbours and bays, implying a level of tolerance to polluted conditions and utilisation of a range of habitat types. This species is reported to be common in southern Japan, an area that has experienced severe coastal degradation, providing further evidence that this species is relatively unimpacted by threats relating to reef degradation.